trigonomitry

A pole 7 meters long is placed against a wall at an angle of 45 degrees, what is the height of the wall

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  1. since the angle is 45º, you have an isosceles right-angled triangle
    so 7 is the hypotenuse and each of the other two sides can be called x

    x^2 + x^2 = 7^2
    2x^2 = 49
    x^2 = 24.5
    x = √24.5 = approx. 4.95 m

    OR

    sin 45º = height of wall/7
    height of wall = 7sin45º
    = 7(.7071067)
    = appr. 4.95 m

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    posted by Reiny
  2. If the top of the pole (of length L) rests on the top of the wall, the wall height H is such that
    sin 45 = H/L = (sqrt2)/2
    Solve for H

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    posted by drwls
  3. Use a trig function that states
    opposite/hypotenuse.

    Of course, this would be the sine function.

    sin(45degrees) = h/7meters

    Let h = height of building

    sin45 = h/7

    sin45 times 7 = h

    4.949747468 = h

    Round 4.949747468 to the nearest tenths becomes 4.95 meters.

    The height of the building is about
    4.95 meters in height.

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    posted by Guido

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